1. Field of the Invention
This invention relates broadly to surgery. More particularly, this invention relates to methods of performing minimally invasive surgical procedures, tissue anchors, and tissue anchor deployment devices.
2. State of the Art
Hernia is a general term used to describe a bulge or protrusion of an organ through the structure or muscle that usually contains. One type of hernia is a ventral hernia, and occurs in the midline of the abdominal wall, usually above the navel (umbilicus). A ventral hernia may be congenital but is most often acquired as a result of a prior surgical incision. In fact, incisional hernias are reported to occur in approximately 4% to 10% of patients after open surgical procedures. Certain risk factors predispose patients to develop incisional ventral hernias, including obesity, diabetes, respiratory insufficiency (lung disease), steroids, wound contamination, postoperative wound infection, smoking, inherited disorders such as Marfan's syndrome and Ehlers-Danlos syndrome, as well as poor surgical technique. A ventral hernia must be surgically repaired. Approximately 90,000-100,000 ventral hernia repairs are performed annually in the United States.
Throughout most of the history of surgery and often today, ventral hernia repair was and is performed by another open procedure. That is, the abdomen is surgically incised over the area of the hernia, with the incision carried down carefully through the sequential tissue layers. The goal is to separate away all the normal tissue and define the margins of the hole or weakness. Once this has been achieved, the hole is then closed, usually by some combination of suture and a plastic mesh. When a repair is done by suture alone, the edges of the defect are pulled together, much like sewing a hole together in a piece of cloth. One of the problems with this approach is that it can put excessive strain on the surrounding tissues through which the sutures are passed. Over time, with normal bodily exertion, this strain can lead to the tearing of these stressed tissues and the formation of another hernia.
In order to provide a secure repair and avoid the stress on the adjacent tissue caused by pulling the hole closed, the hole or weakness is often bridged with a piece of plastic-like mesh or screen material. The mesh is a permanent material and, when sewn to the margins of the defect, it allows the body's normal healing process to incorporate it into the local structures.
While this repair is effective, the trauma to the patient from the procedure can present significant issues for the patient, including extended recovery time. Moreover, there is the danger of complication as prolonged exposure of surgical wounds to the open environment heightens the chance of infections even in presumably sterile settings.
In the last decade or so, a minimally invasive surgical approach to ventral hernia repair has become possible and more commonly used. In this approach, several laparoscopic instruments are introduced through small incisions into the abdomen. The instruments include a visualization scope, a pressurization pathway to insufflate the abdomen, and two or more manipulating instruments (e.g., grasping forceps, staplers, tackers, suturing devices, etc.). The instruments are manipulated to introduce and place the mesh under the hernia defect with a wide margin of mesh outside the defect. The mesh is anchored into place with suture and/or secured to the anterior abdominal wall with a varying number of tacks, placed laparoscopically. The mesh minimizes tension on the repair. The instruments are removed and the several wounds extending into the abdominal cavity are closed.
Minimally invasive surgery results in less operative trauma for the patient. It is also less expensive, reduces hospitalization time, causes less pain and scarring, and reduces the incidence of complications related to the surgical trauma, speeding the recovery. However, even in minimally invasive procedures through the abdomen, wounds are made in the body that are of such significant dimension that they need to be stapled or sutured closed after instrument removal. Such wounds are subject to pain and discomfort, and are a site for adhesions.